Project Summary Adrenocortical carcinoma (ACC) is an aggressive, fatal cancer with five-year survival less than 35%. Surgery remains the only chance of a cure; however, many tumors are unresectable at time of presentation. Lack of human ACC research models has significantly limited progress in the field. Recent establishment of Multi- Disciplinary Adrenal Tumor group at University of Colorado (CU) provides an ideal platform for a collaborative research to advance the field. We have recently established the first new human ACC cell lines and ACC patient derived xenografts (PDX). In parallel, using bioinformatic analyses of published databases, I have identified novel kinases dysregulated in ACC. My initial focus is on maternal embryonic leucine zipper kinase (MELK) which is upregulated 5-25-fold in 40-50% of ACC and low or absent in normal adrenal tissue. Increased MELK expression is correlated with a shorter survival in patients with ACC. Preliminary data support my hypothesis that MELK confers an oncogenic signal by increasing tumorigenesis, proliferation and survival in vitro. The goals for this proposal is to use our ACC models to dissect the mechanism and functional significance of dysregulated kinases such as MELK in ACC. Studies will dissect the functional role of MELK and its downstream targets in our newly developed ACC cell lines; identify potential escape mechanisms from MELK inhibition; and examine whether inhibiting MELK with or without blocking escape pathways leads to decrease tumor growth in our new PDX models. My ultimate career goal is to become an independent physician scientist in the area of endocrine neoplasia with a focus in ACC. Towards this goal, my mentored career development program will allow me: 1) to acquire new technical laboratory skills in in vitro and in vivo assays; 2) to expand my training in bioinformatics using genomic and proteomic platforms 3) to expand training into future phase I studies 4) to promote integration of research findings to clinical practice. This proposal includes a strong and diverse mentoring team including Dr. Wierman with extensive mentoring experience and expertise in tumor biology focused on endocrine neoplasia, Dr. Schweppe, a signal transduction expert with extensive experience in genomic and proteomic approaches in tumor biology and Dr. Leong who integrates research from PDX in GI cancer to Phase I studies. They will ensure expertise in experiment design, new laboratory, and clinical research skills, critical data analysis and advice about career development. Collaborators will provide hands on additional training in bioinformatics, as well as development of cutting edge research techniques and models. In addition Dr. Hammer, University of Michigan, an internationally renowned expert in ACC, will provide mentorship to ensure that I am integrated into the ACC community by developing collaborations which will amplify my work. The outcome of these studies will have a significant impact for the field by allowing testing of novel therapeutic targets in newly developed research models with an ultimate aim to translate these studies into human trials of new treatment modalities for patients with ACC.